Micro Device Arrangement in Donor Substrate

ABSTRACT

This disclosure is related to arranging micro devices in the donor substrate by either patterning or population so that there is no interfering with unwanted pads and the non-interfering area in the donor substrate is maximized. This enables to have transfer the devices to receiver substrate with fewer steps.

FIELD OF THE INVENTION

The present disclosure relates to the transferred micro device system integration on a receiver substrate. More specifically, the present disclosure relates to the patterning of micro devices on donor substrate and the landing area on receiver substrate to increase the efficiency of transfer process.

BRIEF SUMMARY

A few embodiments of this description are related to patterning the micro devices on the donor substrate to facilitate selective transfer process. The micro device array may comprise micro light emitting diodes (LEDs), Organic LEDs, sensors, solid state devices, integrated circuits, (micro-electro-mechanical systems) MEMS, and/or other electronic components. Other embodiments are related to patterning the placing of micro devices in respect to the pixel arrays to optimize the micro-device utilizations in selective transfer process. The receiving substrate may be, but is not no limited to, a printed circuit board (PCB), thin film transistor backplane, integrated circuit substrate, or, in one case of optical micro devices such as LEDs, a component of a display, for example a driving circuitry backplane. The patterning of micro device donor substrate and receiver substrate can be used in combination with different transfer technology including but not limited to pick and place with different mechanisms (e.g. electrostatic transfer head, elastomer transfer head, . . . ), or direct transfer mechanism such as dual function pads and more.

In one embodiment, the micro-devices on donor substrates are patterned in clusters. The clusters may have a smaller pitch than the pixels on receiver substrate and the pitch on receiver substrate may not be multiple of the pitch of micro devices on donor substrate. The cluster can be the size of the pixel pitch of the receiver substrate. The area between each cluster is different from the micro device if the pitch of the pixel is not multiple of the micro device pitch in donor substrate.

In another embodiment, the receiver substrate needs to be populated with different type of micro devices and each pixel has different sub-pixels for different type of micro devices. To avoid transferring wrong type of the micro devices to the sub-pixels, the donor substrate is divided into areas in which if there is micro devices without interfering with other micro devices pads on the system substrate during the transfer process and the areas that will interfere with other micro devices pads on the system substrate if there is micro device in those areas.

In one embodiment the micro devices in donor substrate only exist in the areas without interference.

In one embodiment the direction of moving the donor substrate (or direction of moving system substrate) in reference to the system substrate (or in reference to donor substrate) is used to define the no-interfering areas and interfering areas.

In another embodiment, the sub pixel pads for different micro devices are put close to together where the pad distance between at least two pads is smaller than the pitch of the pixel divided by the number of sub-pixels. In one case, the pitch between the pads of sub pixel in one pixel (or adjacent pixels) matches the donor substrate pitch (or being multiple of donor substrate pitch). It is possible that different donor substrates with different micro devices have different pitch. It is possible that the pads for different micro devices have different size. The pad cluster for sub-pixel can be in different area of a pixel in reference to the pixel area. In this case, the pitch between the pads of subpixels can be either of the pitches of the

In one the embodiment, the pad arrangement for different micro devices are aligned either vertically or horizontally.

In another embodiment the pads are aligned in both dimensions.

According to one aspect there is provided a method of integrated device fabrication, the integrated device comprising a plurality pixels each comprising at least one sub-pixel comprising a micro device integrated on a substrate, the method comprising: defining areas in the donor substrate with and without interferences with other micro devices pads and minimizing the areas with interference to improve the micro device utilization.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the disclosure will become apparent upon reading the following detailed description and upon reference to the drawings.

FIG. 1 shows an example of micro device arrangement in a donor substrate.

FIG. 2 shows an example of a receiver substrate pixel with three different sub pixels.

FIG. 3A shows an embodiment of donor substrate that is arranged to interference and non-interference areas based on the receiver substrate.

FIG. 3B shows another embodiment of donor substrate that is arranged to interference and non-interference areas based on the receiver substrate

FIG. 4 shows an embodiment for using a taller pad associated with one of microdevices to improve the non-interfering area.

FIG. 5 shows an cluster pad embodiment to improve the non-interfering area.

FIG. 6A shows a donor substrate embodiment with non-interfering area associated with the pads at the edge of cluster pads.

FIG. 6B shows a donor substrate embodiment with non-interfering area associated with the inside pads of the cluster.

FIG. 7A shows an example of donor substrate and receiver substrate with cluster pads.

FIG. 7B shows another example of donor substrate and receiver substrate with cluster pads.

FIG. 8 shows an example of receiver substrates with pads in the pixel arranged in two directions.

FIG. 9A shows a donor substrate embodiment with non-interfering area associated with the one of the pads in the pixel.

FIG. 9B shows another donor substrate embodiment with non-interfering area associated with the one of the pads in the pixel.

FIG. 9C shows another donor substrate embodiment with non-interfering area associated with the one of the pads in the pixel.

FIG. 9D shows another donor substrate embodiment with non-interfering area associated with the one of the pads in the pixel.

FIG. 10 shows an embodiment for cluster pads to improve the non-interfering area for the pixel pads arranged in two direction.

FIG. 11A shows a donor substrate embodiment with non-interfering area associated with the one of the pads in the cluster.

FIG. 11B shows another donor substrate embodiment with non-interfering area associated with the one of the pads in the cluster.

FIG. 11C shows another donor substrate embodiment with non-interfering area associated with the one of the pads in the cluster.

FIG. 12A shows an example of substrate donor substrate and receiver substrate with cluster pads arranged in two direction.

FIG. 12B shows an example of substrate donor substrate and receiver substrate with cluster pads arranged in two direction.

FIG. 12C shows an example of substrate donor substrate and receiver substrate with cluster pads arranged in two direction.

FIG. 12D shows an example of substrate donor substrate and receiver substrate with cluster pads arranged in two direction.

FIG. 13A shows the pad cluster in a receiver substrate and a donor substrate embodiment with non-interfering area associated with reference to the one of the pads in the cluster.

FIG. 13B shows another donor substrate embodiment with non-interfering area associated with the one of the pads in the cluster.

FIG. 14A shows an example of substrate donor substrate and receiver substrate with cluster pads arranged in two direction.

FIG. 14B shows an example of substrate donor substrate and receiver substrate with cluster pads arranged in two direction.

While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of an invention as defined by the appended claims.

DETAILED DESCRIPTION

The process of transferring micro devices into a receiver substrate consists of pre-processing the devices on a donor substrate (or a temporary substrate), preparing the landing area (or pads) on a receiver substrate and transferring the micro devices from the donor to the receiver substrate, and post processing to enable device functionality. The pre-processing step may include patterning and adding bonding elements. The transfer process may involve bonding of a pre-selected array of micro devices to the receiver substrate followed by removing the donor substrate. Several different selective transfer processes have been already been developed for micro devices.

In this disclosure, pads in a receiver substrate refers to a designated area in receiver substrate to where a micro device is transferred. The pads could be conductive to prepare connection between the micro device and the pixel circuits or connections where the pixel circuits can be underneath the pad or on the side of the pad. The pad could have some form of bonding materials to hold the micro device permanently. The pad can be stack of multi layer to offer more mechanically stable structure and also better functions such as bonding and conductivity capability.

The pads in this description can either provide an electrical connection, or a mechanical connection or just a defined area for transferring micro devices. The shape of pads used in the embodiments are for purpose of illustration and can have any arbitrarly shape. The position of pads in respect to the pixels can be changed without any affect on the embodiments. The orientation of the group of pads in the pixel can be changed. For example, they can be rotated, shifted or moved to different position. The pads can have complex structure consist of different conductive, semiconductor and dielectric layers. The pads can be position on top of other structures such as transistors in the receiver substrate. Also, the pads can be besides other structures on the receiver substrates.

The shape of micro devices used in the embodiments are for purpose of illustration and devices can have different shape. The micro devices can have one or more pads on side that will contact the receiver substrate. The pads can be mechanical, electrical or combination of both.

In one embodiment, a method of arranging micro devices in the donor substrate is described that is used to transfer micro devices to the receiver substrate. In the donor substrate, micro devices are arranged in relation to the pixel area and within the area associated with the pixel the micro devices has a pitch that is smaller than the pixel pitch.

In this arrangement, the pitch between the micro devices at the boundary of two pixels can be different from the pitch of micro devices within the pixel.

In this case, there are more micro devices in the donor substrate than intended/wanted pads in the receiver substrate associated with the donor substrate area. Therefore, the micro devices can interfere with other unwanted/unintended pads in the receiver substrate. Several embodiments in this documents are described to define interfering areas for donor substrate to remove or not populate micro devices in those areas. This embodiments can be used for different micro device arrangement in the donor substrate.

In another embodiment, a method of arranging the micro devices described in donor substrate to avoid interference with unwanted pads where the method includes

-   -   a) defining non-interfering areas where         -   1) the non-interfering areas are spaces in the donor             substrate that are not covered by other unwanted pads during             micro device transfer to receiver substrate or         -   2) will not be covered by pads after offsetting donor or             receiver substrate in certain direction to align at least             one micro device with a wanted pad in the receiver substrate             after at least one micro device different from said micro             device is transferred to a pad different from the said pad             in the receiver substrate.     -   b) arrange micro devices in the non-interfering areas of the         donor substrate

In the receiver substrate described above, one pad on the receiver can have a taller structure and micro device associated with said pad has shorter structure. Thus, there will be no interfering area for such pad.

To increase the non-interfering area, one embodiment is a method of arranging the pads associated with micro device transfer position in the receiver substrate to clusters where within said clusters the pad pitch is smaller than the sub-pixel pitch.

In case of cluster pads, a donor substrate for a pad at the edge of a cluster has arrangement in such way that interfering and non-interfering areas are similar to the pixel area where width of the interfering area is the same as the distance of the other pads from said pad.

In case of cluster, a donor substrate for a pad inside of a cluster has arrangements whose interfering and non-interfering areas are similar to the pixel area and the interfering areas are defined as

-   -   a) Find the distance between the pad and the edge of said         cluster pad     -   b) Pick one micro device as reference device in donor substrate     -   c) Interfering area is defined from the micro device to both         sides similar to the distance of the associated pads to the edge         of cluster.

The pattern of interfering and non-interfering area defined for an area associated with a pixel in donor substrate can be repeated in donor substrate similar to the pixel pitch.

In the remaining area of the donor substrate, patterned (arranged) for the middle pad, associated with each pixel, a column (or row) of micro devices is between interfering areas whose width is larger than the minimum distance of the middle micro device from the edge of said cluster.

In one embodiment to maximize the non-interfering area, the pad pitch within the cluster is the same as micro device pitch in the donor substrate.

In another embodiment to maximize the non-interfering area, the pads are arranged in the two dimensional cluster. The pads in the cluster can be aligned with at least another pad.

In one embodiment, a donor substrate for the pads aligned with other pads in two directions has diagonal interfering areas in reference to the pad cluster orientations and the said area contains other pads and the remaining area associated with a pixel is non-interfering in which micro device can exist

In another embodiment, a donor substrate for the pads aligned with pads in only one direction has the interfering area as

One row including other pads if the said pad is aligned vertically with the other pads or

One column if the said pad is aligned horizontally with another pad

And remaining area associated with a pixel is non-interfering in which micro device can exist

FIG. 1 shows a donor substrate arrangement where it has more micro devices than associated pads in the receiver substrate. In this case, the micro devices has smaller pitch than pixel pitch of receiver substrate in area of donor substrate associated with the pixels. Also, as the pixel pitch may not be multiple of micro device pitch, the micro device pitch between two pixel area may have a different pitch to accommodate the difference between the pixel and micro device pitches.

In traditional pick and place, the devices on transfer head (donor substrate) are transferred at once to a position in the donor substrate. To populate the rest of the receiver substrate or another receiver substrate, one need to repopulate the transfer head or use a new donor substrate. This process requires fast and accurate movement and precision alignment every time. This invention allows to have more devices on donor substrate than what is required to populate the receiver substrate equivalent area. Then the donor substrate (or receiver substrate) is offset to align the remaining set of micro devices with corresponding locations in the receiver substrate. The offset can be done independently or it can be part of moving the donor substrate to the new location in receiver substrate or a new receiver substrate. However, if receiver substrate requires different micro devices that are part of different donor substrates, the extra devices on donor substrate can interfere with the location (pads) assigned to other type of micro devices in receiver substrate. This invention offers different patterning of devices on donor substrate to avoid such issue.

FIG. 2 shows a pixel structure in an receiver substrate. The array can be made of different orientation and combination of this pixel structure. The pixel structure consist of different micro devices and each micro devices can have different pixel circuit or pixel connections. The pads 204, 214, 224 for each micro-device type are put in each designated sub pixel area 202, 212, 222. Here, the substrate shows three pads 204, 214, 224 for three different micro devices. However, one can use more different micro devices. In one array structure, the micro device types (or sub pixel type) only vary in one direction (one directional array structure). In another array type, the micro devices can vary in two or more direction (two directional array). If the donor substrate for each device type has micro devices in all the area, the micro devices in corresponding areas to the pads of the other micro device types can interfere with the pads during the transfer process. In one case, the only micro devices on the area related to its pads on receiver substrate remains on the donor substrate. However, in this case the donor substrate needs to be replaced or refilled after each transfer which can reduce the processing step. Moreover, it can affect the micro device utilization if the reset of micro devices cannot be used. In one aspect of the invention, the donor substrate for each micro device is divided into interfering and non-interfering areas. The micro devices from the interfering areas are removed or not populated. In one aspect of this invention, the micro devices are arranged in a donor substrate to avoid interference with unwanted pads where the method includes

-   -   a) defining non-interfering areas where         -   3) the non-interfering areas are spaces in the donor             substrate that are not covered by other unwanted pads during             micro device transfer to receiver substrate or         -   4) will not be covered by pads after offsetting donor or             receiver substrate in certain direction to align at least             one micro device with a wanted pad in the receiver substrate             after at least one micro device different from said micro             device is transferred to a pad different from the said pad             in the receiver substrate.     -   b) arrange micro devices in the non-interfering areas of the         donor substrate

In one way to define these areas, the directions of offsetting donor substrate (or receiver substrate) in relation to receiver substrate (or donor substrate) are defined. For example, after first set of the micro devices are transferred from the donor substrate, the donor substrate is offset horizontally and vertically. After transferring first set of micro devices from donor substrate into receiver substrate, the donor substrate is either offset horizontally or vertically. The other set of micro devices can be aligned with other related pads and transferred to these pads in a receiver substrate that can be the original receiver substrate or different one. Following procedure is an exemplary process that can be used to identify the interfering and non-interfering area.

-   -   a) The first set of micro devices for transferring to receiver         substrate is used as reference.     -   b) From the reference micro devices draw lines in parallel with         the offsetting direction.     -   c) Draw line in direction of offsets from the corresponding pads         for other type of micro devices in reference to the reference         pads on the donor substrate.     -   d) Identify the closest lines from other types to the lines of         the micro device on the donor substrate.     -   e) Draw a line between the selected lines and the micro device         line. This line has a similar distance from each of the micro         device line and selected lines.     -   f) The areas defined by the new lines and incompeses the micro         device is the non-interfering areas. The other areas are defined         as interfering areas.

FIG. 3A shows one example of defining non-interfering area 304-1 and interfering area 304-2. The pixel area 330 includes both areas. In this case, the micro devices are offset horizontally and vertically. As a result, the width of non-interfering area for each micro device is the half of the sum of the distances between that pad 304 for that micro device and the other adjacent pads 314, 324. In FIG. 3B, the devices are offset horizontally and diagonally. As a result, the non-interfering area has a slope similar to the slope of diagonal offset process. As can be seen in both cases, the non-interfering area 302 is small compared to the interfering area 304.

One solution to address this issue is to have one of the pads to be taller. This device can be the more expensive device or more used in the receiver substrate. However, it can be any other device as well. In this case, the other micro devices should have a taller structure compared to the micro devices associated with taller pad. One method to achieve taller device is to have taller connection pads. The taller pad can be at either side of the device. FIG. 4 shows an exemplary receiver substrate 400 where one of its pads 414 is taller than the other two pads 404, 424. Here, three different micro devices 404-D, 414-D, 424-D are being transferred to the receiver substrate 400 from donor substrates 450-04, 450-14, 450-24. The micro devices 404-D, 424-D associated with the shorter pad structures 404, 424, has taller structure compared to the other micro device 414-D. The same technique can be applied to other combination of micro devices (more or fewer than three micro devices).

In another solution, the pads for different micro devices are set in cluster close to each other. In one embodiment, the circuit or other connections associated with the pads can be defined in sub-pixel structure for ease of implementation. In another embodiment, the circuits and connections can have any other structure. The closer the pads together, the larger the non-interfering area will be. In one case, the distance between two pads can be equal or smaller than ⅓ of the pixel pitch for three different micro devices (three different sub-pixels). For more or fewer sub-pixels (micro device types) similarly the pads are put closer together. In one embodiment, the distance between the pads in the cluster is similar to the micro device pitche. If the different micro devices have the same pitch, the cluster pads will have the same pitch. In another case, the distance between the pads in the cluster is multiple (for example twice) of the pitch of micro devices. In another embodiment, the distance between the pads can be smaller than the pitch of micro devices. FIG. 5 shows a receiver substrate with an example of pad clusters 540. These pads 504 514, 524 can be from the sub-pixels 502, 512, 522 in one pixel 530 or from different pixels. These pads 504, 514, 524 can be in any position in reference to the pixel 530. It is possible that the order and position of the pads 504, 514, 524 are different for different pixels.

FIG. 6A shows the non-interfering 604-1, and interfering 604-2 area for the pad 604 at the edge of the cluster 640. The same structure can be used for the other pad 624 at the other side of the cluster 640. As can be seen the non-interfering areas for the pads at the edge are larger compared to previous cases. For the pad 614 in the middle, the non-interfering area 612-1 and interfering area 614-2 can be a stripe pattern as demonstrated in FIG. 6B. Here, the width of the strip is the same as the distance between middle pad and the other pads. To define the non-interfering areas, following steps can be used

-   -   a) Find the distance between the pad and the edge of said         cluster pad     -   b) Pick one micro device as reference device in donor substrate     -   c) Interfering area is defined from the micro device to both         sides similar to the distance of the associated pads to the edge         of cluster.

The pattern of interfering and non-interfering area defined for an area associated with a pixel in donor substrate can be repeated in donor substrate similar to the pixel pitch.

In the remaining area of the donor substrate, patterned (arranged) for the middle pad, associated with each pixel, a column (or row) of micro devices is between interfering areas whose width is larger than the minimum distance of the middle micro device from the edge of said cluster.

If the distance between the middle pad and the other pads is the same, the ratio of interfering area 614-1 to non-interfering area 614-2 can be the same. Similar to FIG. 3B, here the two areas can have different shape depending on the offsetting direction. Also, similar to FIG. 4, the middle pad can be taller and so in this case the non-interfering area for middle micro device can be the entire donor substrate.

If the micro devices does not have similar pitch, the distance between pads in the cluster can be similar to any of the pitch or each pad can have different distance from the other pads. To improve the non-interfering area, the middle device can be the one with the larger pitch and so using taller pads can help to improve the interfering area.

FIG. 7 shows a case where the pads 704, 714, 724 in receiver substrate 700 have the same pitch as micro devices in donor substrate 750. Position of pads cluster 740 can be different in reference to the pixels 730. The size of pads can be smaller or similar or larger than micro devices. The shape of the micro devices and pads can be anything. In this case, the micro devices are removed (or non populated) from the interfering area on the donor substrate 750. FIG. 7A shows a case for the edge pad 704 (similar structure can be used for 724). Some of micro devices 754 are already transferred and the donor substrate 750 (or receiver substrate 700) is offsetted vertically in reference receiver substrate 700 (or substrate 750) so that another device is aligned with the bare pads 704 (pads to which with no micro device transferred). It can be also done horizontally. In this case, the empty space created by the transferring of micro device 754 will be a new empty area which will be on top of 714 and the empty space that was on top of 714 will be on top of 724. As such there will be no interference caused by the micro devices for the unwanted pads 714 724. One can finish all the micro devices in one column by offsetting vertically first and then move to the next column (for example after finishing column 2, it moves to column 1). However other combinations of vertical and horizontal offsetting can be used. The pixels 750 or the pad clusters 740 can be at angle be either vertically or horizontally. In this case, the rows or the columns of micro device will be tilted as well. In addition, the micro devices can be at angle without pads or pixels being at angles. In this case, the offsetting direction will be toward the angle of the column or the row. FIG. 7B shows similar structure as FIG. 7A for the middle pad 714.

FIG. 8 shows another pixel orientation example 850. Here, the sub-pixels 802, 812, 822 are distributed in the two dimensions. The pads 804, 814, 824 are shown in each corresponding sub-pixel 802, 812, 822 area. The distance between the pads 816, 826, 836, 806, are used to define the interfering and non-interfering areas. The sub-pixels 802, 812, 822 can be aligned in vertical and horizontal orientations (or diagonally). For example, 814 and 824 can be aligned and so 826 can be zero.

FIG. 9 shows some examples for the interfering area and non-interfering areas for different pads. FIG. 9A is for pad 904 based on horizontal and vertical offsetting of micro devices. In this case, the non-interfering 904-1 and interfering area 904-2 can be a combination of boxes around or off from the pads 904, 914, 924. FIG. 9B shows another example of the non-interfering 904-1 and interfering 904-2 areas for pad 904. Here, the denominator of the two non-interfering areas between pad 904 and 914 and pads 904 and 924 is used as the non-interfering area for pad 904. FIG. 9C shows horizontal non-interfering 924-1 and interfering 924-2 areas. For pad 914, the most optimized case is based on diagonal offsetting. FIG. 9D shows the diagonal strips for non-interfering 914-1 and interfering areas 914. Other patterns also can be used with different offsetting direction. In here, also one can use different pad heights as described in FIG. 4 to improve the device utilization for some of the pads.

FIG. 10 shows another example of cluster pad 1040 where the pads 1004, 1014, 1024 are in two dimensions. Similar to FIG. 5, the pads 1004, 1014, 1024 can have different pitch depending on different pitches of micro devices.

FIG. 11A shows the non-interfering 1104-1, and interfering 1104-2 area for the pad 1104 at the edge of the cluster 1140. As it can be seen the non-interfering areas for the pads at the edge are larger compared to previous cases. FIG. 11B shows the non-interfering 1124-1 and interfering 1124-2 areas for pad 1124. For the pad 1114 in the middle, the non-interfering area 1114-1 and interfering area 1114-2 can be diagonal stripe pattern as demonstrated in FIG. 11C. Here, the width of the strip is the same as the distance between middle pad and the other pads. If the distance between the middle pad and the other pads is the same, the ratio of interfering area 1114-1 to non-interfering area 1114-2 can be the same. Similar to FIG. 3B, here the two areas can have different shape depending on the offsetting direction. Also, similar to FIG. 4, the middle pad can be taller and so in this case the non-interfering area for middle micro device can be the entire donor substrate.

FIG. 12 shows a case where the pads 1204, 1214, 1224 in receiver substrate 1200 have the same pitch as micro devices in donor substrate 1250. Position of pads cluster 1240 can be different in reference to the pixels 1230. The size of pads can be smaller or similar or larger than micro devices. The shape of the micro devices and pads can be anything. In this case, the micro devices are removed (or non populated) from the interfering area on the donor substrate 1250. FIG. 12A shows a case for the edge pad 1104. Some of micro devices 1254 are already transferred and the donor substrate 1250 (or receiver substrate 1200) is offsetted vertically in reference receiver substrate 1200 (or substrate 1250) so that another device is aligned with the bare pads 1204 (pads to which with no micro device transferred). It can be also done horizontally. In this case, the empty spaces created by the transferring of micro device 1254 will be a new empty area which will be on top of other pads 1214, 1224. As such there will be no interference caused by the micro devices for the unwanted pads 1214, 1224. One can finish all the micro devices in one column by offsetting vertically first and then move to the next column (for example after finishing column 2, it moves to column 1). However other combinations of vertical and horizontal offsetting can be used. The pixels 1250 or the pad clusters 1240 can be at angle be either vertically or horizontally. In this case, the rows or the columns of micro device will be tilted as well. In addition, the micro devices can be at angle without pads or pixels being at angles. In this case, the offsetting direction will be toward the angle of the column or the row. FIG. 12B shows similar structure as FIG. 12A for the middle pad 1224. However, the interfering area with no micro device is horizontal. FIG. 12C shows the donor substrate 1250 for the middle pad 1214. Here, the interfering area is diagonal and the offsetting is done diagonally, vertically, and horizontally. FIG. 12D is similar structure of pad 1214 but slightly different arrangement for micro devices to maximize the transfer.

FIG. 13A shows the non-interfering 1304-1, and interfering 1304-2 area for the pad 1304 at the edge of the cluster 1340. As it can be seen the non-interfering areas for the pads at the edge are larger compared to previous cases. The same pattern can be used for Pad 1314. For the pad 1314 in the middle, the non-interfering area 1314-1 and interfering area 1314-2 can be vertical stripe pattern as demonstrated in FIG. 13B. Here, the width of the non-interfering area 1314-1 is the same as the distance between middle pad 1314 and the other pads 1304, 1324 in the other pixel. If the distance between the middle pad and the other pads is the same, the ratio of interfering area 1114-1 to non-interfering area 1114-2 can be the same. Similar to FIG. 3B, here the two areas can have different shape depending on the offsetting direction. Also, similar to FIG. 4, one of the pad can be taller and so in this case the non-interfering area for middle micro device can be the entire donor substrate.

FIG. 14 shows a case where the pads 1404, 1414, 1424 in receiver substrate 1400 have the same pitch as micro devices in donor substrate 1450. Position of pads cluster 1440 can be different in reference to the pixels 1430. The size of pads can be smaller or similar or larger than micro devices. The shape of the micro devices and pads can be anything. In this case, the micro devices are removed (or non populated) from the interfering area on the donor substrate 1450. FIG. 14A shows a case for the edge pad 1404. Some of micro devices 1454 are already transferred and the donor substrate 1450 (or receiver substrate 1200) is offsetted vertically in reference receiver substrate 1400 (or substrate 1450) so that another device is aligned with the bare pads 1404 (pads to which with no micro device transferred). It can be also done horizontally. In this case, the empty spaces created by the transferring of micro device 1454 will be a new empty area which will be on top of other pads 1414, 1424. As such there will be no interference caused by the micro devices for the unwanted pads 1414, 1424. One can finish all the micro devices in one column by offsetting vertically first and then move to the next column (for example after finishing column 2, it moves to column 1). However other combinations of vertical and horizontal offsetting can be used. The pixels 1450 or the pad clusters 1440 can be at angle be either vertically or horizontally. In this case, the rows or the columns of micro device will be tilted as well. In addition, the micro devices can be at angle without pads or pixels being at angles. In this case, the offsetting direction will be toward the angle of the column or the row. FIG. 14B shows similar structure as FIG. 14A for the middle pad 1414. However, the interfering area with no micro device is horizontal. 

What is claimed is:
 1. A method of arranging micro devices in the donor substrate, used to transfer micro devices to the receiver substrate, where micro devices are arranged in relation to the pixel area and the micro devices inside the area associated with the pixel has a pitch that is smaller than the pixel pitch.
 2. The arrangement method of claim 1 where the pitch between the micro devices at the boundary of two pixels are different from the pitch of micro devices within the pixel.
 3. A method of arranging the micro devices in donor substrate to avoid interference with unwanted pads where the method includes a) defining non-interfering areas where 5) the non-interfering areas are spaces in the donor substrate that are not covered by other unwanted pads during micro device transfer to receiver substrate or 6) will not be covered by pads after offsetting donor or receiver substrate in certain direction to align at least one micro device with a wanted pad in the receiver substrate after at least one micro device different from said micro device is transferred to a pad different from the said pad in the receiver substrate. b) arrange micro devices in the non-interfering areas of the donor substrate
 4. In the receiver substrate in claim 3, where one pad has a taller structure and micro device associated with the said pad has shorter structure.
 5. A method of arranging the pads associated with micro device transfer position in the receiver substrate to a cluster where within said cluster the pad pitch is smaller than the sub-pixel pitch.
 6. A donor substrate for a pad at the edge of a cluster defined in claim 5 where it has interfering and non-interfering areas similar to the pixel area where width of the interfering area is the same as the combined width of the other pads different from said pad including the space between the pads.
 7. A donor substrate for a pad inside of a cluster defined in claim 5 where it has interfering and non-interfering areas similar to the pixel area where the interfering areas are defined as d) Find the distance between the pad and the edge of said cluster pad e) Pick one micro device as reference device in donor substrate f) Interfering area is defined from the micro device to both sides similar to the distance of the associated pads to the edge of cluster.
 8. The pattern of claim 7 can be repeated in donor substrate similar to the pixel pitch.
 9. In the remaining area of the donor substrate associated with each pixel area in claim 8, the a column (or row) of micro devices is between interfering areas whose the width is larger than the minimum distance of said micro device in claim 7 from the edge of said cluster in claim
 10. A method of claim 5 where the pad pitch within the cluster is the same as micro device pitch in the donor substrate.
 11. A method of claim 5 where the pads are arranged in the two dimensional cluster.
 12. A cluster according to claim 11 where each pad in the cluster is aligned with at least another pad.
 13. A donor substrate for the pads aligned with other pads in two directions defined in claim 12 where it has interfering diagonal in reference to the pads orientations and the said area contains other pads and the remaining area associated with a pixel is non-interfering in which micro device can exist
 14. A donor substrate for the pads aligned with pads in one direction defined in claim 12 where the interfering area is defined as One row including other pads if the said pad is aligned vertically with the other pads or One column if the said pad is aligned horizontally with another pad And remaining area associated with a pixel is non-interfering in which micro device can exist 